io_uring setup parameters about tokio-uring

[FrankReh]

Now with 0.5.5 of the io-uring, there are new ring sizes also, allowing for NVMe passthrough commands, for 5.19+ kernels.

[FrankReh]

@Noah-Kennedy I had thought about making the driver generic around the two traits created by io-uring 0.5.5 like so.

scoped_thread_local!(pub(crate) static CURRENT: Rc<RefCell<Inner<squeue::EntryMarker, cqueue::EntryMarker>>>);

But of course it's not that easy. The compiler wants a fixed size here, and the use of traits means the size isn't known at compile time.

So maybe we want to live with the driver used by this crate being the original sized Uring, and not plan on supporting the NVMe passthrough commands with it. The NVMe passthrough commands could be supported with an additional uring.

[Noah-Kennedy]

I'm going to read up on NVMe passthrough tonight, as I'm not as familiar with that aspect yet.